I'm from a Jewish family. Ironically enough, I think it was my Bar Mitzvah (at age 13) that started me questioning my religion.
Both my parents are atheists, but I didn't know it until very recently. Before my Bar Mitzvah, my family would only go to temple for the major holidays, which ended up being only three or four times per year. We were part of a conservative temple - it was the only one within driving distance - and the services, to me, were long, boring, recitations of prayer after prayer interrupted by an occasional song from the guitar-playing cantor. My parents never took these services seriously, and I recall that most of my time during these holiday services was spent playing with my tie, or my dad's (wearing a suit was a novelty for me at that age).
Other than holiday services, I did jewish sunday school at the temple a few times a month for 4 or 5 years, starting around age 8, leading up to my Bar Mitzvah. I recall asking questions in class that got me glares from the teachers. I learned to stay quiet.
During the intense preparation for my Bar Mitzvah, which consisted of almost daily grilling from and private meetings with my teachers and a seemingly insurmountable amount of memorization, it occurred to me that I never really developed a belief in God and I was convinced that all of the hebrew I was memorizing didn't really have any significance to me. No one ever took the time to check if I believed in what I was learning at the temple. It was assumed that I went along with it all.
So, I went through with it. I memorized my prayers and my blessings, but no one ever bothered to translate any of it into English to allow me to see its significance. I could not find it in me to ask, either.
After the Bar Mitzvah, there was a period of 4 or 5 years when I resisted my parent's requests to go to temple for the holidays. Looking back on it, I was probably best described as totally and completely apathetic towards religion, especially Judaism.
Around my 18th birthday, a friend of mine sent me a link to a website he thought I'd like - something called randi.org. I was a longtime lurker on the forums and I read Randi's commentary regularly. I was repeatedly amazed and overwhelmingly impressed with what I was reading on the site. I learned what critical thinking and skepticism are and I developed a deep appreciation for the world around me as my atheism began to take shape.
I'm 21 now. I'm a junior at Carnegie Mellon in Pittsburgh and I'm enjoying life immensely. I continue to learn from those who are, in my eyes, gods (no pun intended) of skepticism and critical thinking on these boards. I credit this website, and these forums, as a major force that helped make me the student - of university and of life - that I am today.